Remote interference management reference signal transmission

ABSTRACT

A method, base station (BS), user equipment (UE), apparatus, and computer program product for wireless communication are provided. An aggressor BS may cause a remote interference condition for a victim BS, and the victim BS may transmit a reference signal to the aggressor BS to enable a remote interference management (RIM) operation to be performed. However, the aggressor BS may be unable to identify the victim BS based at least in part on the reference signal, and may fail to transmit a reference signal as a response. Further, when the aggressor BS does transmit a reference signal, the victim BS may be unable to identify the aggressor BS. This may reduce an effectiveness of RIM operations. In some aspects, BSs may transmit reciprocal reference signals including identification information to enable effective RIM operations.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/738,819, filed on Sep. 28, 2018, entitled “REMOTE INTERFERENCEMANAGEMENT REFERENCE SIGNAL TRANSMISSION,” which is hereby expresslyincorporated by reference herein.

BACKGROUND Field

Aspects of the present disclosure generally relate to wirelesscommunication, and more particularly to techniques and apparatuses forremote interference management reference signal transmission.

Background

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, and/or the like). Examples of such multiple-accesstechnologies include code division multiple access (CDMA) systems, timedivision multiple access (TDMA) systems, frequency-division multipleaccess (FDMA) systems, orthogonal frequency-division multiple access(OFDMA) systems, single-carrier frequency-division multiple access(SC-FDMA) systems, time division synchronous code division multipleaccess (TD-SCDMA) systems, LTE/LTE-Advanced is a set of enhancements tothe Universal Mobile Telecommunications System (UMTS) mobile standardpromulgated by the Third Generation Partnership Project (3GPP).

A wireless communication network may include a number of base stations(BSs) that can support communication for a number of user equipment(UEs). A UE may communicate with a BS via the downlink and uplink. Thedownlink (or forward link) refers to the communication link from the BSto the UE, and the uplink (or reverse link) refers to the communicationlink from the UE to the BS. As will be described in more detail herein,a BS may be referred to as a Node B, a gNB, an access point (AP), aradio head, a transmit receive point (TRP), a 5G BS, a 5G Node B, and/orthe like.

The above multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless communication devices to communicate on a municipal,national, regional, and even global level. 5G, which may also bereferred to as New Radio (NR), is a set of enhancements to the LTEmobile standard promulgated by the Third Generation Partnership Project(3GPP). 5G is designed to better support mobile broadband Internetaccess by improving spectral efficiency, lowering costs, improvingservices, making use of new spectrum, and better integrating with otheropen standards using OFDM with a cyclic prefix (CP) (CP-OFDM) on thedownlink (DL), using CP-OFDM and/or SC-FDM (e.g., also known as discreteFourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), as wellas supporting beamforming, multiple-input multiple-output (MIMO) antennatechnology, and carrier aggregation. However, as the demand for mobilebroadband access continues to increase, there exists a need for furtherimprovements in LTE and 5G technologies. Preferably, these improvementsshould be applicable to other multiple access technologies and thetelecommunication standards that employ these technologies.

In most scenarios, a downlink signal of a base station is onlyobservable within and around the edges of coverage areas of cellsprovided by the base station. In some scenarios, however, the downlinksignal of the base station may propagate far beyond the coverage area(e.g., by tens of kilometers, hundreds of kilometers, etc.) as a resultof atmospheric ducting; reflections by mountains, the ocean surface, orclouds; and/or the like. In such a case, the downlink signal of the basestation may create interference for another base station, which may betermed a remote interference condition. The base station that transmitsthe downlink signal may be referred to as an aggressor base station andthe base station that receives the downlink signal may be referred to asa victim base station. In some cases, interference may be reciprocal,such that a first base station is an aggressor to a second base station(which is thus a victim), and the second base station is an aggressor tothe first base station (which is thus a victim). In some cases, aplurality of base stations may be aggressors and/or victims. Forexample, communications of a victim base station may be interfered withby transmissions from a plurality of aggressor base stations.

One situation where such interference may occur is when the aggressorbase station and the victim base station have the same time divisionduplexing (TDD) configuration. This may occur because the aggressor basestation and the victim base station are far apart, so normalinterference countermeasures (e.g., different TDD configurations, gaps,etc.) do not take into account both the victim base station and theaggressor base station. A downlink signal of the aggressor base station,with the propagation delay between the aggressor base station and thevictim base station, may overlap into an uplink portion of the victimbase station's frame configuration. This may cause interference betweenthe victim base station and uplink communications to the victim basestation.

The victim base station, the aggressor base station, and/or anotherdevice (e.g., a UE associated with the victim base station, a networkdevice, an operation/administration/management device, etc.) may performone or more remote interference management (RIM) operations to mitigateremote interference. In some cases, two or more devices may coordinateto perform RIM operations to mitigate remote interference. For example,the victim base station and the aggressor base station may alterrespective communication configurations to reduce a likelihood ofoverlap between downlink transmissions of the aggressor base station anduplink transmissions of the victim base station. Similarly, theaggressor base station may alter a transmit power, a transmit angle,and/or the like to reduce a likelihood that transmissions of theaggressor base station interfere with communications of the victim basestation, and the victim base station may alter a gain value, a receiveangle, and/or the like to reduce a likelihood of receiving transmissionsof the aggressor base station. Base stations may transmit referencesignals to enable measurement of channel conditions and/or interference,which may enable the base stations to determine a RIM operation that maybe successful in mitigating remote interference.

However, in cases where a plurality of aggressor base stations interferewith a single victim base station, the victim base station may receive aplurality of reference signals, and may only be able to determine anamount of aggregate interference, rather than a contribution of eachbase station to a remote interference condition. In this case, victimbase station may be unable to successfully select a RIM operation toperform, to identify an aggressor base station to cause the aggressorbase station to perform a RIM operation, and/or the like. Further, insome cases, only one of the victim base station or the aggressor basestation may transmit a reference signal when a remote interferencecondition is detected. As a result, for example, the victim base stationmay be able to determine remote interference based at least in part on areceived reference signal, but the aggressor base station may not beable to determine remote interference. This may result in lesssuccessful RIM operations being selected, the aggressor base stationfailing to perform any RIM operation, a reciprocal remote interferencecondition failing to be mitigated, and/or the like.

SUMMARY

Some aspects described herein may enable improved remote interferencemanagement (RIM) reference signal transmission. For example, a firstbase station (e.g., a victim base station) may detect an interferencecondition, and may transmit a reference signal that includes informationidentifying the first base station. In this case, a second base station(e.g., an aggressor base station that receives the reference signal) maydetermine an identity of the first base station, which may assist in thesecond base station determining a RIM operation (e.g., such as changinga transmit angle to avoid a location at which the first base station ispositioned). Similarly, the second base station, as a response toreceiving the first reference signal, may transmit a second referencesignal that includes information identifying the second base station. Inthis case, the first base station may determine an identity of thesecond base station, which may assist the first base station indetermining a RIM operation (e.g., such as by enabling the first basestation to distinguish between the second base station and one or moreother base stations that are contributing to the interferencecondition). In this way, an efficacy of RIM operations is improved,thereby reducing a likelihood of interference in a network, improvingnetwork performance, reducing a likelihood of dropped packets and/orlost communications, and/or the like.

In an aspect of the disclosure, a method, a base station (BS), anapparatus, and a computer program product are provided.

In some aspects, the method may by performed by a first base station.The method may include transmitting, based at least in part on anoccurrence of a remote interference condition, a first reference signal,wherein the first reference signal corresponds to a first deviceidentifier identifying the first base station. The method may includereceiving, after transmitting the first reference signal, a secondreference signal, wherein the second reference signal corresponds to asecond device identifier identifying a second base station.

In some aspects, the first base station may include a memory and one ormore processors coupled to the memory. The memory and the one or moreprocessors may be configured to transmit, based at least in part on anoccurrence of a remote interference condition, a first reference signal,wherein the first reference signal corresponds to a first deviceidentifier identifying the first base station. The memory and the one ormore processors may be configured to receive, after transmitting thefirst reference signal, a second reference signal, wherein the secondreference signal corresponds to a second device identifier identifying asecond base station.

In some aspects, the apparatus may include means for transmitting, basedat least in part on an occurrence of a remote interference condition, afirst reference signal, wherein the first reference signal correspondsto a first device identifier identifying the apparatus. The apparatusmay include means for receiving, after transmitting the first referencesignal, a second reference signal, wherein the second reference signalcorresponds to a second device identifier identifying a base station.

In some aspects, the computer program product may include anon-transitory computer-readable medium storing one or moreinstructions. The one or more instructions, when executed by one or moreprocessors of a first base station, may cause the one or more processorsto transmit, based at least in part on an occurrence of a remoteinterference condition, a first reference signal, wherein the firstreference signal corresponds to a first device identifier identifyingthe first base station. The one or more instructions, when executed bythe one or more processors of the first base station, may cause the oneor more processors to receive, after transmitting the first referencesignal, a second reference signal, wherein the second reference signalcorresponds to a second device identifier identifying a second basestation.

In some aspects, the method may by performed by a first base station.The method may include receiving a first reference signal associatedwith a remote interference condition, wherein the first reference signalcorresponds to a first device identifier identifying a second basestation. The method may include transmitting, after receiving the firstreference signal, a second reference signal as a response to receivingthe first reference signal, wherein the second reference signalcorresponds to a second device identifier identifying the first basestation.

In some aspects, the first base station may include a memory and one ormore processors coupled to the memory. The memory and the one or moreprocessors may be configured to receive a first reference signalassociated with a remote interference condition, wherein the firstreference signal corresponds to a first device identifier identifying asecond base station. The memory and the one or more processors may beconfigured to transmit, after receiving the first reference signal, asecond reference signal as a response to receiving the first referencesignal, wherein the second reference signal corresponds to a seconddevice identifier identifying the first base station.

In some aspects, the apparatus may include means for receiving a firstreference signal associated with a remote interference condition,wherein the first reference signal corresponds to a first deviceidentifier identifying a base station. The apparatus may include meansfor transmitting, after receiving the first reference signal, a secondreference signal as a response to receiving the first reference signal,wherein the second reference signal corresponds to a second deviceidentifier identifying the apparatus.

In some aspects, the computer program product may include anon-transitory computer-readable medium storing one or moreinstructions. The one or more instructions, when executed by one or moreprocessors of a first base station, may cause the one or more processorsto receive a first reference signal associated with a remoteinterference condition, wherein the first reference signal correspondsto a first device identifier identifying a second base station. The oneor more instructions, when executed by the one or more processors of thefirst base station, may cause the one or more processors to transmit,after receiving the first reference signal, a second reference signal asa response to receiving the first reference signal, wherein the secondreference signal corresponds to a second device identifier identifyingthe first base station.

Aspects generally include a method, apparatus, system, computer programproduct, non-transitory computer-readable medium, user equipment, basestation, wireless communication device, and processing system assubstantially described herein with reference to and as illustrated bythe accompanying drawings and specification.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is diagram illustrating an example of a wireless communicationnetwork.

FIG. 2 is a diagram illustrating an example of a base station incommunication with a user equipment (UE) in a wireless communicationnetwork.

FIG. 3 is a diagram illustrating an example of a framework for RIMreference signal transmission.

FIG. 4 is a diagram illustrating an example of a framework for RIMreference signal transmission.

FIG. 5 is a diagram illustrating an example of a framework for RIMreference signal transmission.

FIG. 6 is a flow chart of a method of wireless communication.

FIG. 7 is a flow chart of a method of wireless communication.

FIG. 8 is a conceptual data flow diagram illustrating the data flowbetween different modules/means/components in an example apparatus.

FIG. 9 is a diagram illustrating an example of a hardware implementationfor an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purposes of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well-known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, modules, components,circuits, steps, processes, algorithms, and/or the like (collectivelyreferred to as “elements”). These elements may be implemented usingelectronic hardware, computer software, or any combination thereof.Whether such elements are implemented as hardware or software dependsupon the particular application and design constraints imposed on theoverall system.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions,and/or the like, whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions describedmay be implemented in hardware, software, firmware, or any combinationthereof. If implemented in software, the functions may be stored on orencoded as one or more instructions or code on a computer-readablemedium. Computer-readable media includes computer storage media. Storagemedia may be any available media that can be accessed by a computer. Byway of example, and not limitation, such computer-readable media cancomprise a random-access memory (RAM), a read-only memory (ROM), anelectrically erasable programmable ROM (EEPROM), compact disk ROM(CD-ROM) or other optical disk storage, magnetic disk storage or othermagnetic storage devices, combinations of the aforementioned types ofcomputer-readable media, or any other medium that can be used to storecomputer executable code in the form of instructions or data structuresthat can be accessed by a computer.

It is noted that while aspects may be described herein using terminologycommonly associated with 3G and/or 4G wireless technologies, aspects ofthe present disclosure can be applied in other generation-basedcommunication systems, such as 5G and later, including 5G technologies.

FIG. 1 is a diagram illustrating a network 100 in which aspects of thepresent disclosure may be practiced. The network 100 may be an LTEnetwork or some other wireless network, such as a 5G network. Wirelessnetwork 100 may include a number of BSs 110 (shown as BS 110 a, BS 110b, BS 110 c, and BS 110 d) and other network entities. A BS is an entitythat communicates with user equipment (UEs) and may also be referred toas a base station, a 5G BS, a Node B, a gNB, a 5G NB, an access point, atransmit receive point (TRP), and/or the like. Each BS may providecommunication coverage for a particular geographic area. In 3GPP, theterm “cell” can refer to a coverage area of a BS and/or a BS subsystemserving this coverage area, depending on the context in which the termis used.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or another type of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). A BS for a macro cell may bereferred to as a macro BS. A BS for a pico cell may be referred to as apico BS. A BS for a femto cell may be referred to as a femto BS or ahome BS. In the example shown in FIG. 1, a BS 110 a may be a macro BSfor a macro cell 102 a, a BS 110 b may be a pico BS for a pico cell 102b, and a BS 110 c may be a femto BS for a femto cell 102 c. A BS maysupport one or multiple (e.g., three) cells. The terms “eNB”, “basestation”, “5G BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” maybe used interchangeably herein. In some cases, a first BS may interferewith a second BS that is outside of a cell of the first BS, which mayresult in a remote interference condition.

In some examples, a cell may not necessarily be stationary, and thegeographic area of the cell may move according to the location of amobile BS. In some examples, the BSs may be interconnected to oneanother and/or to one or more other BSs or network nodes (not shown) inthe access network 100 through various types of backhaul interfaces suchas a direct physical connection, a virtual network, and/or the likeusing any suitable transport network.

Wireless network 100 may also include relay stations. A relay station isan entity that can receive a transmission of data from an upstreamstation (e.g., a BS or a UE) and send a transmission of the data to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that can relay transmissions for other UEs. In the example shown inFIG. 1, a relay station 110 d may communicate with macro BS 110 a and aUE 120 d in order to facilitate communication between BS 110 a and UE120 d. A relay station may also be referred to as a relay BS, a relaybase station, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs ofdifferent types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/orthe like. These different types of BSs may have different transmit powerlevels, different coverage areas, and different impact on interferencein wireless network 100. For example, macro BSs may have a high transmitpower level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relayBSs may have lower transmit power levels (e.g., 0.1 to 2 Watts).

A network controller 130 may couple to a set of BSs and may providecoordination and control for these BSs. Network controller 130 maycommunicate with the BSs via a backhaul. The BSs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelessnetwork 100, and each UE may be stationary or mobile. A UE may also bereferred to as an access terminal, a terminal, a mobile station, asubscriber unit, a station, etc. A UE may be a cellular phone (e.g., asmart phone), a personal digital assistant (PDA), a wireless modem, awireless communication device, a handheld device, a laptop computer, acordless phone, a wireless local loop (WLL) station, a tablet, a camera,a gaming device, a netbook, a smartbook, an ultrabook, a medical deviceor equipment, biometric sensors/devices, wearable devices (smartwatches, smart clothing, smart glasses, smart wrist bands, smart jewelry(e.g., smart ring, smart bracelet)), an entertainment device (e.g., amusic or video device, or a satellite radio), a vehicular component orsensor, smart meters/sensors, industrial manufacturing equipment, aglobal positioning system device, or any other suitable device that isconfigured to communicate via a wireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolvedor enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEsinclude, for example, robots, drones, remote devices, sensors, meters,monitors, location tags, etc., that may communicate with a base station,another device (e.g., remote device), or some other entity. A wirelessnode may provide, for example, connectivity for or to a network (e.g., awide area network such as Internet or a cellular network) via a wired orwireless communication link. Some UEs may be consideredInternet-of-Things (IoT) devices, and/or may be implemented as NB-IoT(narrowband internet of things) devices. Some UEs may be considered aCustomer Premises Equipment (CPE). UE 120 may be included inside ahousing that houses components of UE 120, such as processor components,memory components, and/or the like.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular RAT andmay operate on one or more frequencies. A RAT may also be referred to asa radio technology, an air interface, and/or the like. A frequency mayalso be referred to as a carrier, a frequency channel, and/or the like.Each frequency may support a single RAT in a given geographic area inorder to avoid interference between wireless networks of different RATs.In some cases, 5G RAT networks may be deployed.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within thescheduling entity's service area or cell. Within the present disclosure,as discussed further below, the scheduling entity may be responsible forscheduling, assigning, reconfiguring, and releasing resources for one ormore subordinate entities. That is, for scheduled communication,subordinate entities utilize resources allocated by the schedulingentity. In some aspects, scheduling of access to the air interface maybe adjusted to avoid a collision between downlink transmissions of afirst base station and uplink transmissions to a second base station, asmay occur during an interference condition.

Base stations are not the only entities that may function as ascheduling entity. That is, in some examples, a UE may function as ascheduling entity, scheduling resources for one or more subordinateentities (e.g., one or more other UEs). In this example, the UE isfunctioning as a scheduling entity, and other UEs utilize resourcesscheduled by the UE for wireless communication. A UE may function as ascheduling entity in a peer-to-peer (P2P) network, and/or in a meshnetwork. In a mesh network example, UEs may optionally communicatedirectly with one another in addition to communicating with thescheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

As indicated above, FIG. 1 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 1.

FIG. 2 shows a block diagram 200 of a design of base station 110 and UE120, which may be one of the base stations and one of the UEs in FIG. 1.Base station 110 may be equipped with T antennas 234 a through 234 t,and UE 120 may be equipped with R antennas 252 a through 252 r, where ingeneral T≥1 and R≥1.

At base station 110, a transmit processor 220 may receive data from adata source 212 for one or more UEs, select one or more modulation andcoding schemes (MCS) for each UE based at least in part on channelquality indicators (CQIs) received from the UE, process (e.g., encodeand modulate) the data for each UE based at least in part on the MCSselected for the UE, and provide data symbols for all UEs. Transmitprocessor 220 may also process system information (e.g., for semi-staticresource partitioning information (SRPI), and/or the like) and controlinformation (e.g., CQI requests, grants, upper layer signaling, and/orthe like) and provide overhead symbols and control symbols. Transmitprocessor 220 may also generate reference symbols for reference signals(e.g., the CRS) and synchronization signals (e.g., the primarysynchronization signal (PSS) and secondary synchronization signal(SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor230 may perform spatial processing (e.g., precoding) on the datasymbols, the control symbols, the overhead symbols, and/or the referencesymbols, if applicable, and may provide T output symbol streams to Tmodulators (MODs) 232 a through 232 t. Each modulator 232 may process arespective output symbol stream (e.g., for OFDM and/or the like) toobtain an output sample stream. Each modulator 232 may further process(e.g., convert to analog, amplify, filter, and upconvert) the outputsample stream to obtain a downlink signal. T downlink signals frommodulators 232 a through 232 t may be transmitted via T antennas 234 athrough 234 t, respectively. According to various aspects described inmore detail below, the synchronization signals can be generated withlocation encoding to convey additional information. In some aspects,base station 110 may configure communication parameters, such as atransmit angle, a transmit power, and/or the like of an antenna 234 toavoid causing a remote interference condition for another base station110. Similarly, base station 110 may configure a gain value, a receiveangle, and/or the like of antenna 234 to avoid interference caused byanother base station 110 in an interference condition.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other base stations and may providereceived signals to demodulators (DEMODs) 254 a through 254 r,respectively. Each demodulator 254 may condition (e.g., filter, amplify,downconvert, and digitize) a received signal to obtain input samples.Each demodulator 254 may further process the input samples (e.g., forOFDM and/or the like) to obtain received symbols. A MIMO detector 256may obtain received symbols from all R demodulators 254 a through 254 r,perform MIMO detection on the received symbols if applicable, andprovide detected symbols. A receive (RX) processor 258 may process(e.g., demodulate and decode) the detected symbols, provide decoded datafor UE 120 to a data sink 260, and provide decoded control informationand system information to a controller/processor 280. A channelprocessor may determine RSRP, RSSI, RSRQ, CQI, and/or the like.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) fromcontroller/processor 280. Transmit processor 264 may also generatereference symbols for one or more reference signals. The symbols fromtransmit processor 264 may be precoded by a TX MIMO processor 266 ifapplicable, further processed by modulators 254 a through 254 r (e.g.,for DFT-s-OFDM, CP-OFDM, and/or the like), and transmitted to basestation 110. At base station 110, the uplink signals from UE 120 andother UEs may be received by antennas 234, processed by demodulators232, detected by a MIMO detector 236 if applicable, and furtherprocessed by a receive processor 238 to obtain decoded data and controlinformation sent by UE 120. Receive processor 238 may provide thedecoded data to a data sink 239 and the decoded control information tocontroller/processor 240. Base station 110 may include communicationunit 244 and communicate to network controller 130 via communicationunit 244. Network controller 130 may include communication unit 294,controller/processor 290, and memory 292.

Controller/processor 240 of base station 110, controller/processor 280of UE 120, and/or any other component(s) of FIG. 2 may perform one ormore techniques associated with RIM reference signal transmission, asdescribed in more detail elsewhere herein. For example,controller/processor 240 of base station 110, controller/processor 280of UE 120, and/or any other component(s) of FIG. 2 may perform or directoperations of, for example, method 600 of FIG. 6, method 700 of FIG. 7,and/or other processes as described herein. Memories 242 and 282 maystore data and program codes for BS 110 and UE 120, respectively. Ascheduler 246 may schedule UEs for data transmission on the downlinkand/or uplink.

As indicated above, FIG. 2 is provided merely as an example. Otherexamples may differ from what is described with regard to FIG. 2.

5G may refer to radios configured to operate according to a new airinterface (e.g., other than Orthogonal Frequency Divisional MultipleAccess (OFDMA)-based air interfaces) or fixed transport layer (e.g.,other than Internet Protocol (IP)). In aspects, 5G may utilize OFDM witha CP (herein referred to as cyclic prefix OFDM or CP-OFDM) and/or SC-FDMon the uplink, may utilize CP-OFDM on the downlink and include supportfor half-duplex operation using TDD. In aspects, 5G may, for example,utilize OFDM with a CP (herein referred to as CP-OFDM) and/or discreteFourier transform spread orthogonal frequency-division multiplexing(DFT-s-OFDM) on the uplink, may utilize CP-OFDM on the downlink andinclude support for half-duplex operation using TDD. 5G may includeEnhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g.,80 megahertz (MHz) and beyond), millimeter wave (mmW) targeting highcarrier frequency (e.g., 60 gigahertz (GHz)), massive MTC (mMTC)targeting non-backward compatible MTC techniques, and/or missioncritical targeting ultra-reliable low latency communications (URLLC)service.

A single component carrier bandwidth of 100 MHZ may be supported. 5Gresource blocks may span 12 sub-carriers with a sub-carrier bandwidth of75 kilohertz (kHz) over a 0.1 ms duration. Each radio frame may include50 subframes with a length of 10 ms. Consequently, each subframe mayhave a length of 0.2 ms. Each subframe may indicate a link direction(e.g., DL or UL) for data transmission and the link direction for eachsubframe may be dynamically switched. Each subframe may include DL/ULdata as well as DL/UL control data.

Beamforming may be supported and beam direction may be dynamicallyconfigured. MIMO transmissions with precoding may also be supported.MIMO configurations in the DL may support up to 8 transmit antennas withmulti-layer DL transmissions up to 8 streams and up to 2 streams per UE.Multi-layer transmissions with up to 2 streams per UE may be supported.Aggregation of multiple cells may be supported with up to 8 servingcells. Alternatively, 5G may support a different air interface, otherthan an OFDM-based interface. 5G networks may include entities suchcentral units or distributed units.

The RAN may include a central unit (CU) and distributed units (DUs). A5G BS (e.g., gNB, 5G Node B, Node B, transmit receive point (TRP),access point (AP)) may correspond to one or multiple BSs. 5G cells canbe configured as access cells (ACells) or data only cells (DCells). Forexample, the RAN (e.g., a central unit or distributed unit) canconfigure the cells. DCells may be cells used for carrier aggregation ordual connectivity, but not used for initial access, cellselection/reselection, or handover. In some aspects, DCells may nottransmit synchronization signals. In some aspects, DCells may transmitsynchronization signals. 5G BSs may transmit downlink signals to UEsindicating the cell type. Based at least in part on the cell typeindication, the UE may communicate with the 5G BS. For example, the UEmay determine 5G BSs to consider for cell selection, access, handover,and/or measurement based at least in part on the indicated cell type.

FIG. 3 is a diagram illustrating an example 300 of a framework for RIMreference signal transmission. As shown in FIG. 3, example 300 includesan aggressor BS 110 and a victim BS 110.

At 305 and 310, victim BS 110 may receive transmissions subject to aremote interference condition, and may detect the remote interferencecondition. For example, aggressor BS 110 may transmit data to one ormore UEs in a cell of aggressor BS 110 that may cause interference tovictim BS 110. In other words, aggressor BS 110 may cause a remoteinterference condition for victim BS 110. In this case, victim BS 110may determine that the remote interference condition is occurring basedat least in part on the transmissions causing interference tocommunications of victim BS 110.

At 315, aggressor BS 110 may start reference signal monitoring. Forexample, aggressor BS 110 may start monitoring for a reference signaltransmission from victim BS 110. In some aspects, aggressor BS 110 maymonitor for reference signals after detecting the remote interferencecondition. For example, aggressor BS 110 may begin monitoring for areference signal associated with a RIM request from victim BS 110 basedat least in part on aggressor BS 110 detecting the remote interferencecondition. Alternatively, aggressor BS 110 may start reference signalmonitoring before detecting the remote interference condition. Forexample, aggressor BS 110 may periodically monitor for reference signalswithout previously detecting the remote interference condition.

At 320, victim BS 110 may transmit, and aggressor BS 110 may receive afirst reference signal (RS-1). The first reference signal may include anidentifier of victim BS 110. For example, victim BS 110 may transmit thereference signal to aggressor BS 110, which indicates that a remoteinterference condition is occurring. In this way, victim BS 110 maytrigger aggressor BS 110 to perform a RIM operation. Moreover, victim BS110 may trigger aggressor BS 110 to transmit a reference signal as aresponse. The response reference signal may enable victim BS 110 toperform a RIM operation.

In some aspects, victim BS 110 may include an explicit base stationidentifier in the first reference signal. For example, victim BS 110 mayinclude a complete base station identifier, a portion of a base stationidentifier, and/or the like in the first reference signal. In this way,victim BS 110 ensures that aggressor BS 110 is enabled to determine anamount of interference attributable to victim BS 110. Moreover, victimBS 110 enables aggressor BS 110 to differentiate interference of victimBS 110 from, for example, one or more other reference signals from oneor more other victim BSs or aggressor BSs. Moreover, victim BS 110enables aggressor BS 110 to select a RIM operation with an improvedefficacy relative to selecting a RIM operation without identifyingvictim BS 110. For example, victim BS 110 may enable aggressor BS 110 toidentify a location of victim BS 110 and select a RIM operationassociated with directing transmission signals away from the location ofvictim BS 110 using beamforming.

In some aspects, victim BS 110 may configure the first reference signalto implicitly identify victim BS 110 (without explicitly identifyingvictim BS 110). For example, victim BS 110 may transmit the firstreference signal using a time resource, a frequency resource, a codedivision multiplexing (CDM) resource, and/or the like allocated forvictim BS 110. In this case, aggressor BS 110 may identify victim BS 110based at least in part on the time resource, the frequency resource, theCDM resource, and/or the like. In some aspects, victim BS 110 may use acombination of an explicit identifier and an implicit identifier toenable aggressor BS 110 to identify victim BS 110. For example, victimBS 110 may transmit the first reference signal using a frequencyresource allocated for a plurality of BSs 110 and with a portion of abase station identifier. This may enable aggressor BS 110 to identifyvictim BS 110 from the plurality of BSs 110.

At 325, aggressor BS 110 may transmit and victim BS 110 may receive asecond reference signal (RS-2). The second reference signal may includean identifier of aggressor BS 110. In some aspects, aggressor BS 110 maytransmit the second reference signal as a response to receiving thefirst reference signal from victim BS 110. In this case, the secondreference signal may be associated with information identifyingaggressor BS 110, such as an explicit identifier, an implicitidentifier, a combination of an explicit identifier and an implicitidentifier, and/or the like.

In some aspects, victim BS 110 may transmit a plurality of firstreference signals and/or aggressor BS 110 may transmit a plurality ofsecond reference signals. For example, victim BS 110 may transmit afirst version of the first reference signal that does not includeidentification information to trigger aggressor BS 110 to startmonitoring more extensively for reference signals. In this case,aggressor BS 110 may increase a gain in monitoring for referencesignals, increase a size of resources monitored for reference signals,interrupt a transmission to monitor for reference signals, and/or thelike. Further, victim BS 110 may transmit a second version of the firstreference signal that does include identification information aftertransmitting the first version of the first reference signal. In thisway, aggressor BS 110 may use a first, shorter monitoring period and maytransition to using a second longer monitoring period. The first,shorter monitoring period may not enable aggressor BS 110 to receive abase station identifier. The second, longer monitoring period may enableaggressor BS 110 to receive a base station identifier. In this way,victim BS 110 conserves resources of aggressor BS 110. Similarly,aggressor BS 110 may transmit a plurality of second reference signals ora plurality of versions of the second reference signal, thereby enablingongoing monitoring of the interference condition for victim BS 110.

At 330 and 335, aggressor BS 110 and/or victim BS 110 may perform a RIMoperation. For example, aggressor BS 110 and victim BS 110 may eachperform RIM operations. In some aspects, aggressor BS 110 and victim BS110 may perform the RIM operations based at least in part on the firstreference signal and/or the second reference signal. In some aspects,aggressor BS 110 and victim BS 110 may perform the RIM operations basedat least in part on identifying each other (e.g., using the firstreference signal and the second reference signal).

In some aspects, to perform a RIM operation, aggressor BS 110 may altera transmission parameter. This may mitigate the remote interferencecondition. For example, aggressor BS 110 may alter a transmit power, atransmit angle, a transmit timing, and/or the like to mitigate theremote interference condition. Similarly, victim BS 110 may alter a gainparameter, a reception angle, a transmit angle, a reception timing, atransmit timing, and/or the like to mitigate the remote interferencecondition.

In some aspects, victim BS 110 may communicate with aggressor BS 110 tocause aggressor BS 110 to reduce a transmit power by a particularamount. Victim BS 110 and/or aggressor BS 110 may determine theparticular amount based at least in part on determining that aggressorBS 110 contributes a particular portion of interference to the remoteinterference condition, In this case, victim BS 110 may reduce an amountby which aggressor BS 110 is caused to reduce a transmit power, therebyenabling aggressor BS 110 to transmit with a higher power than if victimBS 110 were unable to identify the contribution of aggressor BS 110.This may improve network performance and reduce remote interference.

In some aspects, aggressor BS 110 and victim BS 110 may continue totransmit reference signals. For example, victim BS 110 may detect thatthe remote interference condition is still occurring after the RIMoperation and may transmit another reference signal. Similarly,aggressor BS 110 may transmit another reference signal. In this case,victim BS 110 and/or aggressor BS 110 may continue to perform RIMoperations to mitigate the remote interference condition.

At 340 and 345, aggressor BS 110 may restore a previous configurationand stop reference signal monitoring. For example, aggressor BS 110 maydetermine the remote interference condition is not occurring after athreshold amount of time without receiving a reference signal. In thiscase, aggressor BS 110 may stop transmission of reference signals tovictim BS 110 and/or may stop monitoring for reference signals fromvictim BS 110. Further, aggressor BS 110 (and/or victim BS 110) mayrestore one or more communication parameters that was changed during aRIM operation to restore earlier communication operating parameters. Insome aspects, aggressor BS 110 (and/or victim BS 110) may maintain oneor more communication parameters that was changed during the RIMoperation to avoid a reoccurrence of the interference condition.

As indicated above, FIG. 3 is provided as an example. Other examples arepossible and may differ from what was described with respect to FIG. 3.

FIG. 4 is a diagram illustrating an example 400 of a framework for RIMsignal transmission.

At 405 and 410, victim BS 110 may receive transmissions subject to aremote interference condition. Victim BS 110 may detect the remoteinterference condition based at least in part on receiving thetransmissions. For example, aggressor BS 110 may transmit data to one ormore UEs in a cell of aggressor BS 110. In this case, transmissions ofaggressor BS 110 may interfere with communications of another cell inwhich victim BS 110 is attempting to communicate. In other words,aggressor BS 110 may transmit information that interferes withcommunication by victim BS 110. In this case, victim BS 110 maydetermine that the remote interference condition is occurring.

At 415, 420, and 425, victim BS 110 may start reference signalmonitoring. Further, victim BS 110 may transmit a first reference signaland aggressor BS 110 may receive the first reference signal (RS-1). Thefirst reference signal may include information identifying victim BS110. For example, victim BS 110 may transmit the first reference signalto aggressor BS 110 to indicate to aggressor BS 110 that a remoteinterference condition is occurring. Additionally, or alternatively,victim BS 110 may transmit the first reference signal to trigger a RIMoperation, to trigger aggressor BS 110 to transmit a second referencesignal as a response, and/or the like.

At 430, aggressor BS 110 may transmit a backhaul notification to victimBS 110. For example, aggressor BS 110 may transmit the backhaulnotification to indicate that the first reference signal is detected. Insome aspects, aggressor BS 110 may transmit the backhaul notification toprovide information regarding the first reference signal. For example,aggressor BS 110 may provide information identifying an amount ofinterference detected at aggressor BS 110 based at least in part on thefirst reference signal. This may enable victim BS 110 to perform a RIMoperation. In this way, aggressor BS 110 uses a backhaul connection toincrease a reliability of reporting information regarding the firstreference signal relative to including the information in a message sentvia an access connection.

At 435, aggressor BS 110 may transmit, and victim BS 110 may receive asecond reference signal (RS-2). The second reference signal may includean identifier of aggressor BS 110. For example, aggressor BS 110 maytransmit a second reference signal to victim BS 110 as a response toreceiving the first reference signal from victim BS 110. In this case,the second reference signal may include information identifyingaggressor BS 110. In some aspects, victim BS 110 may provide a responsemessage, such as using a backhaul notification.

At 440 and 445, aggressor BS 110 and/or victim BS 110 may perform a RIMoperation. For example, aggressor BS 110 and victim BS 110 may performthe RIM operation using information included in the first referencesignal and/or the second reference signal. Additionally, oralternatively, victim BS 110 and/or aggressor BS 110 may perform the RIMoperation based at least in part on the information identifying victimBS 110 and aggressor BS 110 in the first reference signal and the secondreference signal, respectively. In some aspects, to perform the RIMoperation, aggressor BS 110 and/or victim BS 110 may alter acommunication parameter to mitigate the remote interference condition.

At 450, 455, and 460, victim BS 110 may stop transmission of referencesignals to aggressor BS 110. Further, aggressor BS 110 may stopreference signal monitoring and restore a previous transmissionconfiguration. Further, aggressor BS 110 may provide a notification tovictim BS 110. In this case, aggressor BS 110 may provide thenotification via a backhaul to indicate that no reference signal isdetected within a threshold period of time. Further, aggressor BS 110may provide the notification to indicate that aggressor BS 110 is torestore a previous transmission configuration. In this way, aggressor BS110 avoids prematurely stopping RIM operations (e.g., because of failingto receive reference signals as a result of the interference condition)by using the backhaul to indicate whether aggressor BS 110 is to stopRIM operations. This may enable victim BS 110 to confirm whether theinterference condition is no longer occurring.

As indicated above, FIG. 4 is provided as an example. Other examples arepossible and may differ from what was described with respect to FIG. 4.

FIG. 5 is a diagram illustrating an example 500 of a framework for RIMreference signal transmission.

At 505 and 510, victim BS 110 may receive transmissions subject to aremote interference condition. Further, victim BS 110 may detect theremote interference condition based at least in part on receiving thetransmissions. For example, aggressor BS 110 may transmit data to one ormore UEs in a cell of aggressor BS 110 and the transmissions ofaggressor BS 110 may interfere with communications by victim BS 110. Inthis case, victim BS 110 may determine, based at least in part on thetransmissions causing interference to communications of victim BS 110that the remote interference condition is occurring.

At 515, 520, and 525, victim BS 110 may start reference signalmonitoring. Further, victim BS 110 may transmit a first referencesignal. Further, aggressor BS 110 may receive the first reference signal(RS-1). For example, victim BS 110 may transmit the first referencesignal to aggressor BS 110 to indicate to aggressor BS 110 that a remoteinterference condition is occurring. Additionally, or alternatively,victim BS 110 may transmit the first reference signal to trigger a RIMoperation, to trigger aggressor BS 110 to transmit a second referencesignal as a response, and/or the like. In this case, the first referencesignal may be associated with information identifying victim BS 110,such as an explicit identifier, an implicit identifier, and/or the like.

At 530, aggressor BS 110 may transmit a backhaul notification to victimBS 110. For example, aggressor BS 110 may transmit the backhaulnotification to indicate that the first reference signal is detected. Insome aspects, aggressor BS 110 may transmit the backhaul notification toprovide information regarding the first reference signal. For example,aggressor BS 110 may provide information associated with theinterference condition, such as an amount of interference detected ataggressor BS 110 based at least in part on the first reference signal,which may enable victim BS 110 to perform a RIM operation.

At 535, aggressor BS 110 may transmit, and victim BS 110 may receive asecond reference signal (RS-2). The second reference signal may includean identifier of aggressor BS 110. For example, aggressor BS 110 maytransmit the second reference signal to victim BS 110 based at least inpart on receiving the first reference signal. In this case, the secondreference signal may be associated with information identifyingaggressor BS 110. In some aspects, the first reference signal and thesecond reference may convey identifiers that identify respectivetransmitting BSs 110. For example, aggressor BS 110 may transmit thesecond reference signal to convey an identifier of aggressor BS 110 andvictim BS 110 may transmit the first reference signal to convey anidentifier of victim BS 110.

At 540, victim BS 110 may transmit a backhaul RIM coordination message.For example, victim BS 110 may transmit information identifying a resultof aggressor BS 110 transmitting the second reference signal. In thiscase, victim BS 110 may indicate an amount of interference attributableto aggressor BS 110. Additionally, or alternatively, victim BS 110 maytransmit an instruction regarding altering a communication configurationin connection with a RIM operation, to enable aggressor BS 110 to alterthe communication configuration. In some aspects, aggressor BS 110 maytransmit a response message via the backhaul to indicate a RIM operationthat aggressor BS 110 is to perform. Additionally, or alternatively,aggressor BS 110 may transmit the response message to acknowledgereceipt of the backhaul RIM coordination message. In this way, victim BS110 improves a likelihood of success of a RIM operation relative touncoordinated RIM operations relative to using messages transmitted viaan access network transmission. Moreover, victim BS 110 improves areliability of RIM operation coordination relative to using messagestransmitted via an access network transmission.

At 545 and 550, aggressor BS 110 and/or victim BS 110 may perform a RIMoperation. For example, using the first reference signal and the secondreference signal, and based at least in part on the informationidentifying victim BS 110 and aggressor BS 110 in the first referencesignal and the second reference signal, respectively, and the backhaulRIM coordination message, aggressor BS 110 and victim BS 110 may performthe RIM operation.

At 555, 560, and 565, victim BS 110 may stop transmission of referencesignals to aggressor BS 110. Further, aggressor BS 110 may stopreference signal monitoring and restore a previous transmissionconfiguration. Further, aggressor BS 110 may provide a backhaulnotification to victim BS 110. Additionally, or alternatively, aggressorBS 110 may maintain a changed transmission configuration. In this case,aggressor BS 110 may provide the notification via a backhaul to indicatethat no reference signal is detected within a threshold period of time,and that aggressor BS 110 is to restore a previous transmissionconfiguration.

As indicated above, FIG. 5 is provided as an example. Other examples arepossible and may differ from what was described with respect to FIG. 5.

FIG. 6 is a flow chart of a method 600 of wireless communication. Themethod may be performed by a first base station (BS) (e.g., the BS 110,the aggressor BS 110, the victim BS 110, the apparatus 802/802′, thebase station 850, and/or the like).

At 610, in some aspects, the first base station may detect a remoteinterference condition. For example, the first base station (e.g., usingantenna 234, DEMOD 232, MIMO detector 236, receive processor 238,controller/processor 240, and/or the like) may detect the remoteinterference condition, as described in more detail above. In this case,the first base station may detect interference in a communication with,for example, a user equipment, and may be triggered to perform a RIMoperation.

At 620, the first base station may transmit a first reference signal.For example, the first base station (e.g., using controller/processor240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna234, and/or the like) may transmit, based at least in part on anoccurrence of a remote interference condition, a first reference signal,as described in more detail above. In some aspects, the first referencesignal corresponds to a first device identifier identifying the firstbase station (e.g., a base station identifier). In this way, the firstbase station, which may be a victim base station, may trigger a RIMoperation for the aggressor base station, and may trigger the aggressorbase station to transmit a second reference signal as a response toenable the first base station to perform a RIM operation.

At 630, the first base station may receive a second reference signal.For example, the first base station (e.g., using antenna 234, DEMOD 232,MIMO detector 236, receive processor 238, controller/processor 240,and/or the like) may receive, after transmitting the first referencesignal, a second reference signal, as described in more detail above. Insome aspects, the second reference signal corresponds to a second deviceidentifier identifying a second base station. In this way, the firstbase station may determine one or more parameter value changes as a RIMoperation, to enable a reduction in interference.

At 640, in some aspects, the first base station may perform a RIMoperation. For example, the first base station (e.g., using antenna 234,DEMOD 232, MIMO detector 236, receive processor 238,controller/processor 240, and/or the like) may perform the RIMoperation, as described in more detail above. In this case, the firstbase station may adjust a communication parameter value, may communicatewith the second base station to cause the second base station to adjusta communication parameter value, and/or the like.

Method 600 may include additional aspects, such as any single aspect orany combination of aspects described below and/or in connection with oneor more other processes described elsewhere herein.

In a first aspect, the first base station is configured to perform aremote interference management operation based at least in part on thesecond reference signal.

In a second aspect, alone or in combination with the first aspect, thefirst device identifier is at least a portion of a base stationidentifier identifying the first base station.

In a third aspect, alone or in combination with one or more of the firstthrough second aspects, the second device identifier is at least aportion of a base station identifier identifying the second basestation.

In a fourth aspect, alone or in combination with one or more of thefirst through third aspects, a configuration of the first referencesignal corresponds to the first device identifier, and wherein theconfiguration of the first reference signal relates to at least one of atime resource allocated to the first reference signal, a frequencyresource allocated to the first reference signal, or a code divisionmultiplexing resource allocated to the first reference signal.

In a fifth aspect, alone or in combination with one or more of the firstthrough fourth aspects, a configuration of the second reference signalcorresponds to the second device identifier, and wherein theconfiguration of the second reference signal is at least one of a timeresource allocated to the second reference signal, a frequency resourceallocated to the second reference signal, or a code divisionmultiplexing resource allocated to the second reference signal.

In a sixth aspect, alone or in combination with one or more of the firstthrough fifth aspects, method 700 includes determining, based at leastin part on the second reference signal, at least one of a presence ofremote interference, an estimated quantity of interfered symbols, or aninterference power estimation.

In a seventh aspect, alone or in combination with one or more of thefirst through sixth aspects, the first reference signal is generatedbased at least in part on the first device identifier.

In an eighth aspect, alone or in combination with one or more of thefirst through seventh aspects, the second reference signal is generatedbased at least in part on the second device identifier.

In a ninth aspect, alone or in combination with one or more of the firstthrough eighth aspects, the first base station is configured to transmita third reference signal that does not include a device identifier.

In a tenth aspect, alone or in combination with one or more of the firstthrough ninth aspects, the first base station is configured to receive afourth reference signal that does not include a device identifier.

In an eleventh aspect, alone or in combination with one or more of thefirst through tenth aspects, the first base station is configured toreceive a backhaul message from the second base station indicatingreception of the first reference signal.

In a twelfth aspect, alone or in combination with one or more of thefirst through eleventh aspects, the first base station is configured toreceive a backhaul message from the second base station indicating athreshold period of time has elapsed since a last reference signal wasreceived.

In a thirteenth aspect, alone or in combination with one or more of thefirst through twelfth aspects, the first base station is configured toend transmission of reference signals based at least in part ondetecting an end to the remote interference condition.

Although FIG. 6 shows example blocks of a method of wirelesscommunication, in some aspects, the method may include additionalblocks, fewer blocks, different blocks, or differently arranged blocksthan those shown in FIG. 6. Additionally, or alternatively, two or moreblocks shown in FIG. 6 may be performed in parallel.

FIG. 7 is a flow chart of a method 700 of wireless communication. Themethod may be performed by a first base station (BS) (e.g., the BS 110,the aggressor BS 110, the victim BS 110, the apparatus 802/802′, thebase station 850, and/or the like).

At 710, the first base station may receive a first reference signal. Forexample, the first base station (e.g., using antenna 234, DEMOD 232,MIMO detector 236, receive processor 238, controller/processor 240,and/or the like) may receive a first reference signal associated with aremote interference condition, as described in more detail above. Insome aspects, the first reference signal corresponds to a first deviceidentifier identifying a second base station. In this case, the firstbase station may be triggered to transmit a second reference signal as aresponse, and may be triggered to perform a RIM operation as a responseto mitigate the remote interference condition.

At 720, the first base station may transmit a second reference signal.For example, the BS (e.g., using controller/processor 240, transmitprocessor 220, TX MIMO processor 230, MOD 232, antenna 234, and/or thelike) may transmit, after receiving the first reference signal, a secondreference signal as a response to receiving the first reference signal,as described in more detail above. In some aspects, the second referencesignal corresponds to a second device identifier identifying the firstbase station. In this case, the BS may include the second deviceidentifier in the second reference signal to enable the second basestation to determine a contribution of the first base station to theinterference condition, thereby improving a likelihood that a RIMoperation is successful at mitigating the interference condition.

At 730, in some aspects, the first base station may perform a RIMoperation. For example, the BS (e.g., using controller/processor 240,transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234,and/or the like) may perform the RIM operation, as described in moredetail above. In this case, the first base station may perform the RIMoperation based at least in part on a measurement of the first referencesignal, based at least in part on receiving information from the secondbase station (e.g., information associated with a measurement of thesecond reference signal by the second base station), and/or the like.

Method 700 may include additional aspects, such as any single aspect orany combination of aspects described below and/or in connection with oneor more other processes described elsewhere herein.

In a first aspect, the first base station is configured to perform aremote interference management operation based at least in part on thefirst reference signal.

In a second aspect, alone or in combination with the first aspect, thefirst device identifier is at least a portion of a base stationidentifier identifying the second base station.

In a third aspect, alone or in combination with any of the first throughsecond aspects, the second device identifier is at least a portion of abase station identifier identifying the first base station.

In a fourth aspect, alone or in combination with any of the firstthrough third aspects, wherein a configuration of the first referencesignal corresponds to the first device identifier, and wherein theconfiguration of the first reference signal is at least one of a timeresource allocated to the first reference signal, a frequency resourceallocated to the first reference signal, or a code division multiplexingresource allocated to the first reference signal.

In a fifth aspect, alone or in combination with any of the first throughfourth aspects, a configuration of the second reference signalcorresponds to the second device identifier, and wherein theconfiguration indicated by the second reference signal is at least oneof a time resource allocated to the second reference signal, a frequencyresource allocated to the second reference signal, or a code divisionmultiplexing resource allocated to the second reference signal.

In a sixth aspect, alone or in combination with any of the first throughfifth aspects, method 700 includes determining, based at least in parton the second reference signal, at least one of: a presence of remoteinterference, an estimated quantity of interfered symbols, or aninterference power estimation.

In a seventh aspect, alone or in combination with any of the firstthrough sixth aspects, the first reference signal is generated based atleast in part on the first device identifier.

In an eighth aspect, alone or in combination with any of the firstthrough seventh aspects, the second reference signal is generated basedat least in part on the second device identifier.

In a ninth aspect, alone or in combination with any of the first througheighth aspects, the first base station is configured to transmit a thirdreference signal that does not include a device identifier.

In a tenth aspect, alone or in combination with any of the first throughninth aspects, the first base station is configured to receive a thirdreference signal that does not include a device identifier.

In an eleventh aspect, alone or in combination with any of the firstthrough tenth aspects, the first base station is configured to transmita backhaul message to the second base station indicating reception ofthe first reference signal.

In a twelfth aspect, alone or in combination with any of the firstthrough eleventh aspects, the first base station is configured totransmit a backhaul message to the second base station indicating athreshold period of time has elapsed since a last reference signal wasreceived.

In a thirteenth aspect, alone or in combination with any of the firstthrough twelfth aspects, the first base station is configured to endtransmission of reference signals based at least in part on detecting anend to the remote interference condition.

Although FIG. 7 shows example blocks of a method of wirelesscommunication, in some aspects, the method may include additionalblocks, fewer blocks, different blocks, or differently arranged blocksthan those shown in FIG. 7. Additionally, or alternatively, two or moreblocks shown in FIG. 7 may be performed in parallel.

FIG. 8 is a conceptual data flow diagram 800 illustrating the data flowbetween different modules/means/components in an example apparatus 802.The apparatus 802 may be a base station. In some aspects, the apparatus802 includes a reception module 804, a detection module 806, adetermination module 808, and/or a transmission module 810.

The reception module 804 may receive, from base station 850 and as data820, information associated with remote interference. For example, thereception module 804 may receive data 820 that may indicate anoccurrence of a remote interference condition, such as based on the data820 being incomplete and/or corrupted. In some aspects, the receptionmodule 804 may receive a reference signal including an identifier ofbase station 850, which may enable the apparatus 802 to determine acontribution of base station 850 to a remote interference condition.

The detection module 806 may receive, from the reception module 804 andas data 822, information associated with detecting an occurrence of aremote interference condition. For example, the detection module 806 mayreceive information identifying a channel condition, a characteristic ofdata received by the reception module 804, and/or the like. In thiscase, the detection module 806 may determine that the remoteinterference condition is occurring and may trigger transmission of areference signal to enable a RIM operation to be performed by theapparatus 802, the base station 850, and/or the like.

The determination module 808 may receive, from the reception module 804and as data 826, information associated with determining acharacteristic of a communication. For example, the determination modulemay determine a presence of remote interference, an estimated quantityof interfered symbols, an interference power estimation, and/or thelike.

The transmission module 810 may receive, from the detection module 806and as data 824 and/or from determination module 808 and as data 828,information associated with an occurrence of a remote interferencecondition. For example, the transmission module 810 may receiveinformation indicating that a remote interference condition is occurringand may transmit data 830 to base station 850, such as a referencesignal including information identifying the apparatus 802, aninstruction to perform a RIM operation, a confirmation that thereception module 804 received a reference signal from the base station850, and/or the like.

The apparatus may include additional modules that perform each of theblocks of the algorithm in the aforementioned method 600 of FIG. 6,method 700 of FIG. 7, and/or the like. As such, each block in theaforementioned method 600 of FIG. 6, method 700 of FIG. 7, and/or thelike may be performed by a module and the apparatus may include one ormore of those modules. The modules may be one or more hardwarecomponents specifically configured to carry out the statedprocesses/algorithm, implemented by a processor configured to performthe stated processes/algorithm, stored within a computer-readable mediumfor implementation by a processor, or some combination thereof.

The number and arrangement of modules shown in FIG. 8 are provided as anexample. In practice, there may be additional modules, fewer modules,different modules, or differently arranged modules than those shown inFIG. 8. Furthermore, two or more modules shown in FIG. 8 may beimplemented within a single module, or a single module shown in FIG. 8may be implemented as multiple, distributed modules. Additionally, oralternatively, a set of modules (e.g., one or more modules) shown inFIG. 8 may perform one or more functions described as being performed byanother set of modules shown in FIG. 8.

FIG. 9 is a diagram 900 illustrating an example of a hardwareimplementation for an apparatus 802′ employing a processing system 902.The apparatus 802′ may be BS.

The processing system 902 may be implemented with a bus architecture,represented generally by the bus 904. The bus 904 may include any numberof interconnecting buses and bridges depending on the specificapplication of the processing system 902 and the overall designconstraints. The bus 904 links together various circuits including oneor more processors and/or hardware modules, represented by the processor906, the modules 804, 806, 808, 810, and the computer-readablemedium/memory 908. The bus 904 may also link various other circuits suchas timing sources, peripherals, voltage regulators, and power managementcircuits, which are well known in the art, and therefore, will not bedescribed any further.

The processing system 902 may be coupled to a transceiver 910. Thetransceiver 910 is coupled to one or more antennas 912. The transceiver910 provides a means for communicating with various other apparatus overa transmission medium. The transceiver 910 receives a signal from theone or more antennas 912, extracts information from the received signal,and provides the extracted information to the processing system 902,specifically the reception module 804. In addition, the transceiver 910receives information from the processing system 902, specifically thetransmission module 810, and based at least in part on the receivedinformation, generates a signal to be applied to the one or moreantennas 912. The processing system 902 includes a processor 906 coupledto a computer-readable medium/memory 908. The processor 906 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 908. The software, whenexecuted by the processor 906, causes the processing system 902 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 908 may also be used forstoring data that is manipulated by the processor 906 when executingsoftware. The processing system further includes at least one of themodules 804, 806, 808, and 810. The modules may be software modulesrunning in the processor 906, resident/stored in the computer-readablemedium/memory 908, one or more hardware modules coupled to the processor906, or some combination thereof. The processing system 902 may be acomponent of the BS 110 and may include the memory 242 and/or at leastone of the TX MIMO processor 230, the RX processor 238, and/or thecontroller/processor 240.

In some aspects, the apparatus 802/802′ for wireless communicationincludes means for transmitting, based at least in part on an occurrenceof a remote interference condition, a first reference signal, whereinthe first reference signal corresponds to a first device identifieridentifying the apparatus 802/802′; means for receiving, aftertransmitting the first reference signal, a second reference signal,wherein the second reference signal corresponds to a second deviceidentifier identifying a base station; and/or the like. In some aspects,the apparatus 802/802′ for wireless communication includes means forreceiving a first reference signal associated with a remote interferencecondition, wherein the first reference signal corresponds to a firstdevice identifier identifying a base station; means for transmitting,after receiving the first reference signal, a second reference signal asa response to receiving the first reference signal, wherein the secondreference signal corresponds to a second device identifier identifyingthe apparatus 802/802′; and/or the like. The aforementioned means may beone or more of the aforementioned modules of the apparatus 802 and/orthe processing system 902 of the apparatus 802′ configured to performthe functions recited by the aforementioned means. As described supra,the processing system 902 may include the TX MIMO processor 230, thereceive processor 238, and/or the controller/processor 240. As such, inone configuration, the aforementioned means may be the TX MIMO processor230, the receive processor 238, and/or the controller/processor 240configured to perform the functions recited by the aforementioned means.

FIG. 9 is provided as an example. Other examples are possible and maydiffer from what was described in connection with FIG. 9.

It is understood that the specific order or hierarchy of blocks in theprocesses/flow charts disclosed is an illustration of exampleapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of blocks in the processes/flow charts maybe rearranged. Further, some blocks may be combined or omitted. Theaccompanying method claims present elements of the various blocks in asample order, and are not meant to be limited to the specific order orhierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” The word “exemplary” is used hereinto mean “serving as an example, instance, or illustration.” Any aspectdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects. Unless specifically statedotherwise, the term “some” refers to one or more. Combinations such as“at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B,C, or any combination thereof” include any combination of A, B, and/orC, and may include multiples of A, multiples of B, or multiples of C.Specifically, combinations such as “at least one of A, B, or C,” “atleast one of A, B, and C,” and “A, B, C, or any combination thereof” maybe A only, B only, C only, A and B, A and C, B and C, or A and B and C,where any such combinations may contain one or more member or members ofA, B, or C. All structural and functional equivalents to the elements ofthe various aspects described throughout this disclosure that are knownor later come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed as a means plus function unless the element is expresslyrecited using the phrase “means for.”

What is claimed is:
 1. A method of wireless communication performed by afirst base station, comprising: transmitting a first reference signalassociated with an occurrence of a remote interference condition,wherein the first reference signal corresponds to a first deviceidentifier identifying the first base station; and receiving, aftertransmitting the first reference signal, a second reference signalincluding information indicating a second device identifier identifyinga second base station.
 2. The method of claim 1, wherein the first basestation is configured to perform a remote interference managementoperation based at least in part on the second reference signal.
 3. Themethod of claim 1, wherein the first device identifier is at least aportion of a base station identifier identifying the first base station.4. The method of claim 1, wherein the second device identifier is atleast a portion of a base station identifier identifying the second basestation.
 5. The method of claim 1, wherein a configuration of the firstreference signal corresponds to the first device identifier, and whereinthe configuration of the first reference signal includes at least oneof: a time resource allocated to the first reference signal, a frequencyresource allocated to the first reference signal, or a code divisionmultiplexing resource allocated to the first reference signal.
 6. Themethod of claim 1, wherein a configuration of the second referencesignal corresponds to the second device identifier, and wherein theconfiguration of the second reference signal includes at least one of: atime resource allocated to the second reference signal, a frequencyresource allocated to the second reference signal, or a code divisionmultiplexing resource allocated to the second reference signal.
 7. Themethod of claim 1, further comprising: determining, based at least inpart on the second reference signal, at least one of: a presence ofremote interference, an estimated quantity of interfered symbols, or aninterference power estimation.
 8. The method of claim 1, wherein thefirst reference signal is generated based at least in part on the firstdevice identifier.
 9. The method of claim 1, wherein the secondreference signal is generated based at least in part on the seconddevice identifier.
 10. The method of claim 1, wherein the first basestation is configured to receive a backhaul message from the second basestation indicating reception of the first reference signal.
 11. Themethod of claim 1, wherein the first base station is configured toreceive a backhaul message from the second base station indicating athreshold period of time has elapsed since a last reference signal wasreceived.
 12. The method of claim 1, wherein the first base station isconfigured to end transmission of reference signals based at least inpart on detecting an end to the remote interference condition.
 13. Amethod of wireless communication performed by a first base station,comprising: receiving a first reference signal associated with anoccurence of a remote interference condition, wherein the firstreference signal corresponds to a first device identifier identifying asecond base station; and transmitting, after receiving the firstreference signal, a second reference signal as a response to receivingthe first reference signal, wherein the second reference signal includesinformation indicating a second device identifier identifying the firstbase station.
 14. The method of claim 13, wherein the first base stationis configured to perform a remote interference management operationbased at least in part on the first reference signal.
 15. The method ofclaim 13, wherein the first device identifier is at least a portion of abase station identifier identifying the second base station.
 16. Themethod of claim 13, wherein the second device identifier corresponds toat least a portion of a base station identifier identifying the firstbase station.
 17. The method of claim 13, wherein a configuration of thefirst reference signal corresponds to the first device identifier, andwherein the configuration of the first reference signal includes atleast one of: a time resource allocated to the first reference signal, afrequency resource allocated to the first reference signal, or a codedivision multiplexing resource allocated to the first reference signal.18. The method of claim 13, wherein a configuration of the secondreference signal corresponds to the second device identifier, andwherein the configuration of the second reference signal includes atleast one of: a time resource allocated to the second reference signal,a frequency resource allocated to the second reference signal, or a codedivision multiplexing resource allocated to the second reference signal.19. The method of claim 13, further comprising: determining, based atleast in part on the first reference signal, at least one of: a presenceof remote interference, an estimated quantity of interfered symbols, oran interference power estimation.
 20. The method of claim 13, whereinthe first reference signal is generated based at least in part on thefirst device identifier.
 21. The method of claim 13, wherein the secondreference signal is generated based at least in part on the seconddevice identifier.
 22. The method of claim 13, wherein the first basestation is configured to transmit a backhaul message to the second basestation indicating reception of the first reference signal.
 23. Themethod of claim 13, wherein the first base station is configured totransmit a backhaul message to the second base station indicating athreshold period of time has elapsed since a last reference signal wasreceived.
 24. The method of claim 13, wherein the first base station isconfigured to end transmission of reference signals based at least inpart on detecting an end to the remote interference condition.
 25. Afirst base station for wireless communication, comprising: memory; andone or more processors coupled to the memory, the memory and the one ormore processors configured to: transmit a first reference signalassociated with an occurence of a remote interference condition, whereinthe first reference signal corresponds to a first device identifieridentifying the first base station; and receive, after transmitting thefirst reference signal, a second reference signal including informationindicating a second device identifier identifying a second base station.26. The first base station of claim 25, wherein the first base stationis configured to perform a remote interference management operationbased at least in part on the second reference signal.
 27. The firstbase station of claim 25, wherein the first device identifier is atleast a portion of a base station identifier identifying the first basestation.
 28. A first base station for wireless communication,comprising: memory; and one or more processors coupled to the memory,the memory and the one or more processors configured to: receive a firstreference signal associated with an occurence of a remote interferencecondition, wherein the first reference signal corresponds to a firstdevice identifier identifying a second base station; and transmit, afterreceiving the first reference signal, a second reference signal as aresponse to receiving the first reference signal, wherein the secondreference signal includes information indicating a second deviceidentifier identifying the first base station.
 29. The first basestation of claim 28, wherein the first base station is configured toperform a remote interference management operation based at least inpart on the first reference signal.
 30. The first base station of claim28, wherein the first device identifier is at least a portion of a basestation identifier identifying the second base station.